A boiler used for heating or warm water is a device configured to heat a desired area or supply warm water by heating water or direct water (hereinafter referred to as a “heating medium”) being heated by a heat source, and the boiler includes a burner configured to combust a mixture of a gas and air and a heat exchanger configured to transfer combustion heat of a combustion gas to the heating medium.
Boilers produced in an early on used a heat exchanger which heats a heating medium using only sensible heat generated when a burner performs a combustion operation, but a condensing boiler, which has a sensible heat exchanger configured to absorb sensible heat of a combustion gas generated in a combustion chamber, and a latent heat exchanger configured to absorb latent heat generated by condensation of water vapor contained in the combustion gas which underwent heat exchange in the sensible heat exchanger, is recently being used to improve thermal efficiency. Such a condensing boiler is being applied to an oil boiler as well as a gas boiler, thereby contributing to an increase in boiler efficiency and a reduction in fuel cost.
As described above, a conventional condensing type heat exchanger including a sensible heat exchanger and a latent heat exchanger is configured with a structure in which a blower, a fuel supply nozzle, and a burner are installed above a housing, and the sensible heat exchanger and the latent heat exchanger, which each have a heat exchange fin coupled to an outer side of a heat exchange tube, are sequentially installed inside the housing below the burner.
However, in the conventional condensing type heat exchanger, there is a problem in that a volume of the heat exchanger is increased due to the blower being disposed above the housing and the structures of the sensible heat exchanger and the latent heat exchanger which are individually installed inside the housing.
As prior art for improving heat exchange efficiency and minimizing a volume while resolving such a problem, Korean Registered Patent No. 10-0813807 discloses a heat exchanger configured with a burner disposed at a central portion of the heat exchanger, and with a heat exchange tube wound around a circumference of the burner in the form of a coil.
The heat exchanger disclosed in the above-described patent has problems in that the tube is deformed into a rounded shape when the tube is formed into a flat shape and a pressure is applied to a heat transfer medium portion, and a thickness of the tube is to be thick since the tube is manufactured by being rolled up.
Further, the conventional heat exchanger is configured with a structure in which a heat exchange tube is wound around a combustion chamber in the form of a coil, and a heating medium flows in only one direction along the heat exchange tube such that there is a disadvantage of being unable to secure a wide heat transfer area since a heat exchange between a combustion gas and the heating medium is performed only in a local space formed around the heat exchanger in the form of a coil.